In recent years, research on technique (hereinafter, referred to as “automated driving”) for automatically controlling at least one of the acceleration/deceleration and the steering of own vehicle is carried on. In connection with this, there is known a forward monitoring promotion device that promotes the forward monitoring by changing a dimming area of a window glass around a driver's seat to a frosted glass state unless a driver performs the forward monitoring during automatic driving operation (for example, see Japanese Patent Application Laid-Open publication No. 2013-095330).